In the manufacturing of a glass plate product, a workpiece is obtained by cutting it out of a raw material, such that the workpiece is in a size that matches the size of the product, and then chamfering is performed on edge portions of the workpiece. Generally speaking, it is desirable that the chamfering angle be about 45°.
Conventionally, chamfering has been performed mainly by a mechanical method using grinding stone. However, in such a mechanical method, cullet is generated and adheres to the workpiece during the chamfering. Therefore, it is necessary to clean the workpiece after the chamfering.
Patent Literature 1 proposes chamfering edge portions by forming laser filaments inside glass (see, in particular, FIGS. 4 and 5). This chamfering technique indicates a possibility of overcoming the drawbacks in conventional chamfering methods.